The difference between mutexes and spin locks

Note the difference between spin lock and mutex lock :
1 Mutex lock will give up cpu during the waiting period (because
preemption is prohibited when trying to obtain $ )

 static inline void spin_lock(spinlock_t *lock)
 {
    
    
 	/*
 	 * Spin locks also need to be removed in order to eliminate all
 	 * memory barriers. They are only used by the write side anyway.
 	 */
 #ifndef NO_SYNC_SMP_MB
 	preempt_disable();
 	lock_impl_lock(&lock->internal_lock);
 #endif
 }

2 Compared with mutex locks, spin locks reduce thread scheduling and save costs.

spin_lock  在单cpu 上  禁止抢占  preempt_disable 
spin_lock_irq  在单cpu 上  关本地中断   local_irq_disable    再 禁止抢占  preempt_disable